From 2600301ba6dbac5c9d640c87007a07ee6dcea1f4 Mon Sep 17 00:00:00 2001
From: "Heiko Schlittermann (HS12-RIPE)" <hs@schlittermann.de>
Date: Mon, 19 Aug 2019 14:45:48 +0200
Subject: [PATCH] string.c: do not interpret '\\' before '\0' (CVE-2019-15846)


--- a/doc/ChangeLog
+++ b/doc/ChangeLog
@@ -4,6 +4,11 @@ This document describes *changes* to pre
 affect Exim's operation, with an unchanged configuration file.  For new
 options, and new features, see the NewStuff file next to this ChangeLog.
 
+Exim version 4.92.2
+-------------------
+
+HS/01 Handle trailing backslash gracefully. (CVE-2019-15846)
+
 
 Since version 4.92
 ------------------
--- a/src/string.c
+++ b/src/string.c
@@ -224,6 +224,8 @@ interpreted in strings.
 Arguments:
   pp       points a pointer to the initiating "\" in the string;
            the pointer gets updated to point to the final character
+           If the backslash is the last character in the string, it
+           is not interpreted.
 Returns:   the value of the character escape
 */
 
@@ -236,6 +238,7 @@ const uschar *hex_digits= CUS"0123456789
 int ch;
 const uschar *p = *pp;
 ch = *(++p);
+if (ch == '\0') return **pp;
 if (isdigit(ch) && ch != '8' && ch != '9')
   {
   ch -= '0';
@@ -1210,8 +1213,8 @@ memcpy(g->s + p, s, count);
 g->ptr = p + count;
 return g;
 }
- 
- 
+
+
 gstring *
 string_cat(gstring *string, const uschar *s)
 {